1 #ifndef _LINUX_VIRTIO_CONFIG_H
2 #define _LINUX_VIRTIO_CONFIG_H
6 #include <linux/virtio.h>
7 #include <uapi/linux/virtio_config.h>
10 * virtio_config_ops - operations for configuring a virtio device
11 * @get: read the value of a configuration field
12 * vdev: the virtio_device
13 * offset: the offset of the configuration field
14 * buf: the buffer to write the field value into.
15 * len: the length of the buffer
16 * @set: write the value of a configuration field
17 * vdev: the virtio_device
18 * offset: the offset of the configuration field
19 * buf: the buffer to read the field value from.
20 * len: the length of the buffer
21 * @get_status: read the status byte
22 * vdev: the virtio_device
23 * Returns the status byte
24 * @set_status: write the status byte
25 * vdev: the virtio_device
26 * status: the new status byte
27 * @reset: reset the device
28 * vdev: the virtio device
29 * After this, status and feature negotiation must be done again
30 * Device must not be reset from its vq/config callbacks, or in
31 * parallel with being added/removed.
32 * @find_vqs: find virtqueues and instantiate them.
33 * vdev: the virtio_device
34 * nvqs: the number of virtqueues to find
35 * vqs: on success, includes new virtqueues
36 * callbacks: array of callbacks, for each virtqueue
37 * include a NULL entry for vqs that do not need a callback
38 * names: array of virtqueue names (mainly for debugging)
39 * include a NULL entry for vqs unused by driver
40 * Returns 0 on success or error status
41 * @del_vqs: free virtqueues found by find_vqs().
42 * @get_features: get the array of feature bits for this device.
43 * vdev: the virtio_device
44 * Returns the first 32 feature bits (all we currently need).
45 * @finalize_features: confirm what device features we'll be using.
46 * vdev: the virtio_device
47 * This gives the final feature bits for the device: it can change
48 * the dev->feature bits if it wants.
49 * @bus_name: return the bus name associated with the device
50 * vdev: the virtio_device
51 * This returns a pointer to the bus name a la pci_name from which
52 * the caller can then copy.
53 * @set_vq_affinity: set the affinity for a virtqueue.
55 typedef void vq_callback_t(struct virtqueue
*);
56 struct virtio_config_ops
{
57 void (*get
)(struct virtio_device
*vdev
, unsigned offset
,
58 void *buf
, unsigned len
);
59 void (*set
)(struct virtio_device
*vdev
, unsigned offset
,
60 const void *buf
, unsigned len
);
61 u8 (*get_status
)(struct virtio_device
*vdev
);
62 void (*set_status
)(struct virtio_device
*vdev
, u8 status
);
63 void (*reset
)(struct virtio_device
*vdev
);
64 int (*find_vqs
)(struct virtio_device
*, unsigned nvqs
,
65 struct virtqueue
*vqs
[],
66 vq_callback_t
*callbacks
[],
68 void (*del_vqs
)(struct virtio_device
*);
69 u32 (*get_features
)(struct virtio_device
*vdev
);
70 void (*finalize_features
)(struct virtio_device
*vdev
);
71 const char *(*bus_name
)(struct virtio_device
*vdev
);
72 int (*set_vq_affinity
)(struct virtqueue
*vq
, int cpu
);
75 /* If driver didn't advertise the feature, it will never appear. */
76 void virtio_check_driver_offered_feature(const struct virtio_device
*vdev
,
80 * virtio_has_feature - helper to determine if this device has this feature.
82 * @fbit: the feature bit
84 static inline bool virtio_has_feature(const struct virtio_device
*vdev
,
87 /* Did you forget to fix assumptions on max features? */
88 if (__builtin_constant_p(fbit
))
89 BUILD_BUG_ON(fbit
>= 32);
93 if (fbit
< VIRTIO_TRANSPORT_F_START
)
94 virtio_check_driver_offered_feature(vdev
, fbit
);
96 return test_bit(fbit
, vdev
->features
);
100 * virtio_config_val - look for a feature and get a virtio config entry.
101 * @vdev: the virtio device
102 * @fbit: the feature bit
103 * @offset: the type to search for.
104 * @v: a pointer to the value to fill in.
106 * The return value is -ENOENT if the feature doesn't exist. Otherwise
107 * the config value is copied into whatever is pointed to by v. */
108 #define virtio_config_val(vdev, fbit, offset, v) \
109 virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
111 #define virtio_config_val_len(vdev, fbit, offset, v, len) \
112 virtio_config_buf((vdev), (fbit), (offset), (v), (len))
114 static inline int virtio_config_buf(struct virtio_device
*vdev
,
117 void *buf
, unsigned len
)
119 if (!virtio_has_feature(vdev
, fbit
))
122 vdev
->config
->get(vdev
, offset
, buf
, len
);
127 struct virtqueue
*virtio_find_single_vq(struct virtio_device
*vdev
,
128 vq_callback_t
*c
, const char *n
)
130 vq_callback_t
*callbacks
[] = { c
};
131 const char *names
[] = { n
};
132 struct virtqueue
*vq
;
133 int err
= vdev
->config
->find_vqs(vdev
, 1, &vq
, callbacks
, names
);
140 const char *virtio_bus_name(struct virtio_device
*vdev
)
142 if (!vdev
->config
->bus_name
)
144 return vdev
->config
->bus_name(vdev
);
148 * virtqueue_set_affinity - setting affinity for a virtqueue
152 * Pay attention the function are best-effort: the affinity hint may not be set
153 * due to config support, irq type and sharing.
157 int virtqueue_set_affinity(struct virtqueue
*vq
, int cpu
)
159 struct virtio_device
*vdev
= vq
->vdev
;
160 if (vdev
->config
->set_vq_affinity
)
161 return vdev
->config
->set_vq_affinity(vq
, cpu
);
166 #endif /* _LINUX_VIRTIO_CONFIG_H */
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